JP6697319B2 - Automatic braking device for vehicles - Google Patents

Description

  The present invention provides a vehicle automatic control system capable of immediately avoiding brake responsiveness even when the flow rate of brake fluid is reduced by a brake operation not intended to be braked by the driver. Brake device.

  Conventionally, a vehicle automatic brake device that operates the main brake as needed even when the driver has released the brake pedal has been known. The brake assist control device, the automatic emergency braking device, and the skid prevention It is already functioning in a control device, an inter-vehicle distance maintenance control device, a lane departure prevention support device, and the like.

  This vehicle automatic brake device, for example, as disclosed in Japanese Unexamined Patent Application Publication No. 2016-2013, discloses a wheel in which the hydraulic pressure of a master cylinder is sucked by an electric pump and is increased to require braking. A solenoid valve that communicates with a wheel cylinder provided in the vehicle is opened, and hydraulic pressure is supplied to the wheel cylinder to engage and brake the brake caliper. Even if the driver depresses the brake pedal to make an emergency stop, if the pedaling force is weak and it is difficult to make an emergency stop of the vehicle, the brake assist control is activated and the driver The pedal effort of is assisted.

JP, 2016-201330, A

  When the driver releases the brake pedal, the reservoir tank in which the brake fluid is stored is communicated with the master cylinder through the master port. Therefore, the automatic brake device disclosed in the above-mentioned document is used. Is activated, the brake fluid stored in the reservoir tank is supplied to the wheel cylinders via the master cylinder by driving the electric pump. On the other hand, when the driver depresses the brake pedal, the master port shuts off the master port. Therefore, the brake fluid in the master cylinder is supplied to the wheel cylinder by the drive of the electric pump to perform the brake assist.

  By the way, when the driver gently depresses the brake pedal with his toes, the master piston may slightly move and the opening area of the master port may be narrowed due to the slight movement of the brake pedal.

  If the master port is throttled when the automatic brake device operates, the passage resistance when sucking the brake fluid stored in the reservoir tank by the electric pump increases, and the flow rate ratio decreases. There is an inconvenience that the brake response is deteriorated.

  In view of the above circumstances, the present invention, even when the brake pedal operation by the driver's extremely gentle pedaling force, reduces the flow rate ratio by narrowing the opening area of the master port that connects the reservoir tank and the master cylinder, An object of the present invention is to provide an automatic braking device for a vehicle, which can immediately recover the brake responsiveness.

The present invention relates to a brake operating section operated by a driver, and a master cylinder that is connected to the brake operating section and that generates a brake fluid pressure with an operation amount of a master piston according to an operation amount of the brake operating section. connects a reservoir tank for supplying the brake fluid through the master port on the master cylinder, a wheel cylinder for generating a braking force to the wheel by the brake fluid pressure from the master cylinder, and said master cylinder and said wheel cylinder A hydraulic circuit, a pressure accumulating means provided in the hydraulic circuit for accumulating the brake fluid supplied to the hydraulic circuit, and a brake fluid change amount calculating means for obtaining a change amount of the brake fluid passing through the hydraulic circuit. And when the automatic brake operating condition is satisfied, the hydraulic pump interposed in the hydraulic circuit is driven, and the brake fluid on the master cylinder side is supplied to the wheel cylinder independently of the operation of the brake operating unit. In the vehicle automatic brake device, the brake control means monitors the amount of change of the brake fluid supplied to the wheel cylinder when the automatic brake operating condition is satisfied. The brake fluid monitoring means further includes means, and when the change amount obtained by the brake fluid change amount calculating means deviates from a preset specified value, the brake fluid on the master cylinder side is supplied to the hydraulic pump. After accumulating pressure in the pressure accumulating means via, the measured physical quantity that detects the supply state of the brake fluid to the hydraulic circuit and the set physical quantity are compared, and when the measured physical quantity reaches the set physical quantity, the pressure accumulating means is stored. Brake fluid drawing processing is performed to shut off the accumulated pressure of brake fluid.

  According to the present invention, when the amount of change in the brake fluid passing through the hydraulic circuit during automatic brake operation deviates from a preset specified value, the brake fluid accumulated in the master cylinder is sucked and accumulated in the pressure accumulating means. Therefore, if the opening area of the master port that connects the reservoir tank and the master cylinder is reduced by the master piston when the driver operates the brake pedal with an extremely gentle depressing force, pull the master piston in Can be blocked. Then, after that, by shutting off the fluid path to the pressure accumulating means, the brake fluid staying in the master cylinder can be immediately supplied to the wheel cylinders, the decrease in the flow rate ratio can be suppressed, and the brake responsiveness can be immediately restored. You can

Schematic diagram of automatic braking system for vehicles (A) is a partial cross-sectional side view of the brake fluid pressure generation part in an open state, (b) is a partial cross-sectional side view of the brake fluid pressure generation part in a state where the brake pedal is stepped on with an extremely gentle depressing force. Brake control unit schematic configuration diagram Flowchart showing the brake fluid monitoring routine Flowchart showing the master piston retracting routine (A) is a cross-sectional view of the master cylinder showing the state of the master piston when the brake pedal is stepped on with an extremely gentle depressing force, and (b) of the master cylinder showing the state in which the brake fluid in the master cylinder is drawn. Sectional view

  An embodiment of the present invention will be described below with reference to the drawings. The automatic brake device according to the present embodiment mainly includes a brake fluid pressure generation unit 1 and a brake fluid pressure circuit 2 shown in FIG. 1, and a brake control unit 3 as brake control means shown in FIG. The brake control unit 3 is provided with a brake fluid monitoring unit 3a as a brake fluid monitoring means.

  The brake fluid pressure generating unit 1 includes a master cylinder 4, a reservoir tank 5 attached to the master cylinder 4, and a brake pedal 7 as a brake operating unit that is connected to the master cylinder 4 via a brake booster 6. The brake fluid is stored in the reservoir tank 5. A brake pedal 7 is connected to the brake booster 6 via an operating rod 8.

  As shown in FIG. 2, the master cylinder 4 is of a tandem type, in which the first and second master pistons 9a and 9b are slidably inserted, and the brake booster 6 is connected to the push rod of the second master piston 9b. 9 are connected in series. In the master cylinder 4, a first hydraulic chamber 11a is defined by the first master piston 9a, and a second hydraulic chamber 11b is defined between the first and second master pistons 9a and 9b. .

  Further, the first and second hydraulic springs 11a and 11b are respectively provided with the first and second compression springs 12a and 12b, whereby the first master piston 9a is driven by the first compression spring 12a to the second master. The second master piston 9b is constantly biased toward the piston 9b, and the second master piston 9b is biased toward the brake booster 6 by the biasing force of the second compression spring 12b. Further, the reservoir tank 5 and the hydraulic chambers 11a and 11b are communicated with each other via the first and second master ports 5a and 5b, respectively.

  Further, the master cylinder 4 and the wheel cylinders 13 a to 13 d of the brake caliper, which is a constituent element of the main brake provided on each wheel 15 a to 15 d of the vehicle, are communicated with each other via the brake hydraulic circuit 2. As shown in FIG. 1, the brake hydraulic circuit 2 is composed of two systems, a first hydraulic circuit 22 and a second hydraulic circuit 23. The brake hydraulic circuit 2 according to the present invention is a cross pipe or a front and rear pipe, and the first hydraulic circuit 22 is provided on the wheel cylinders 13a and 13b of the brake caliper provided on the front right and rear left or the front left and right wheels 15a and 15b. The second hydraulic circuit 23 is connected and is connected to the wheel cylinders 13c and 13d of the brake caliper provided on the front left and rear right or the rear left and right wheels 15c and 15d.

  Since the first hydraulic circuit and the second hydraulic circuit have the same configuration, the same reference numerals are given below to simplify the description. Further, in describing the configuration of the brake hydraulic circuits 22 and 23 below, for convenience, on the basis of the flow from the master cylinder 4 to the wheel cylinders 13a to 13d side of the brake caliper, the master cylinder 4 side is upstream, The wheel cylinders 13a to 13d side will be described as the downstream side.

  The master cylinder 4 is provided with first and second supply / discharge ports 14a, 14b communicating with the first and second hydraulic pressure chambers 11a, 11b, and the first liquid passage is provided in each of the supply / discharge ports 14a, 14b. The upstream of L1 is connected, and the downstream is connected in the middle of the second liquid path L2. The upstream side of the second liquid passage L2 is connected to a low pressure accumulator 24 as a pressure accumulating means. Further, the downstream side of the second liquid passage L2 is branched and connected to the third liquid passage L3 and the fourth liquid passage L4, and the downstream sides of the respective liquid passages L3, L4 are the wheels 15a, 15b (15c, 15d). It is connected to the wheel cylinders 13a, 13b (13c, 13d) that operate the brake calipers provided in the above to generate a braking force on the wheels 15a, 15b (15c, 15d).

  On the other hand, the upstream of the fifth and sixth liquid passages L5 and L6 are connected to the middle of the third and fourth liquid passages L3 and L4, and the downstream of the fifth and sixth liquid passages L5 and L6 becomes the seventh liquid passage. The low pressure accumulator 24 is connected to the downstream side of the seventh liquid passage L7.

  A gate-in valve 25 is provided in the first liquid passage L1, and a hydraulic pump 26 is provided in the second liquid passage L2 downstream of the first liquid passage L1. Further, the hydraulic pumps 26 of the first and second hydraulic circuits 22 and 23 are connected to a common electric motor 27.

  Further, the first liquid passage L1 on the upstream side of the gate-in valve 25 and the second liquid passage L2 on the downstream side of the hydraulic pump 26 are bypass-connected via the eighth liquid passage L8. A bypass valve 28 is provided in L8. Further, a first brake fluid detecting means 29a (second brake fluid detecting means 29b) is provided downstream of the eighth fluid passage L8 in the second fluid passage L2. The brake fluid detection means 29a (29b) is a fluid pressure sensor that detects the fluid pressure of the brake fluid discharged from the fluid pressure pump 26, a flow rate sensor that detects the flow rate, and the like. Further, pressurizing valves 30 and 31 are provided in the third and fourth liquid passages L3 and L4, and pressure reducing valves 32 and 33 are provided in the fifth and sixth liquid passages L5 and L6.

  Each of these valves 25, 28, 30 to 33 (collectively referred to as "brake actuator" in FIG. 3) is an electromagnetic solenoid valve, and is switched according to an automatic brake drive signal from the brake control unit 3. The brake control unit 3 is mainly composed of a microcomputer, and has a well-known CPU, ROM, RAM, and non-volatile memory, and the like. The ROM is a fixed program represented by various programs and maps. Data and the like are stored. Further, the brake control unit 3 has a function of executing the brake fluid monitoring unit 3a shown in FIG.

  The brake fluid monitoring unit 3a is activated by the automatic brake drive signal output from the brake control unit 3 as a trigger, and first, the automatic brake operation is performed based on the brake fluid characteristics detected by the first and second brake fluid detection means 29a and 29b. The rising change amount at the time is obtained, and it is checked whether or not this change amount is within the regulation (normal). A master piston retracting process is performed in which the existing brake fluid is sucked toward the first and second hydraulic circuits 22 and 23 and the master pistons 9a and 9b are retracted in the braking operation direction.

  The brake fluid monitoring unit 3a specifically monitors the brake fluid characteristics according to the brake fluid monitoring routine shown in FIG. In this routine, first, in step S1, it is checked whether or not the automatic brake drive signal output from the brake control unit 3 is detected.

  When the driver releases the brake pedal 7 or when the amount of depression of the brake pedal 7 is small, the automatic brake applies the brake independently of the driver's braking operation as necessary. It operates. The automatic brake drive signal is output when a preset automatic braking operation condition is satisfied by a brake assist control device, an automatic emergency braking device, a skid prevention control device, an inter-vehicle distance maintenance control device, a lane departure prevention support device, etc. Then, the automatic brake operates.

  When the automatic brake is inactive, the electric motor 27 is stopped and therefore the hydraulic pump 26 is also stopped. In this state, the gate-in valve 25 is closed, the bypass valve 28, the pressurizing valves 30 and 31 are opened, and the depressurizing valves 32 and 33 are closed.

  Therefore, when the driver depresses the brake pedal 7, the brake fluid pressure generated in the first and second fluid pressure chambers 11a and 11b of the master cylinder 4 is changed to the first fluid passage L1, the eighth fluid passage L8, and the second fluid passage. It is supplied to the wheel cylinders 13a to 13d of the brake caliper provided on the wheels 15a to 15d by branching to the third liquid path L3 and the fourth liquid path L4 via the path L2. Then, a brake force is generated on each of the wheels 15a to 15d by this brake hydraulic pressure.

  On the other hand, when the automatic brake drive signal is output from the brake control unit 3, the electric motor 27 is driven, the bypass valve 28 and the pressure reducing valves 32 and 33 are closed, and the gate-in valve 25 and the pressurizing valves 30 and 31 are closed. Is opened. As a result, the hydraulic pump 26 is rotated by the drive of the electric motor 27, and is stored in the reservoir tank 5 via the first and second hydraulic chambers 11a and 11b of the master cylinder 4 independently of the operation of the brake pedal 7. The brake fluid that has been applied is sucked into the first fluid passage L1.

  Then, the brake fluid sucked into the first liquid passage L1 is branched into the third liquid passage L3 and the fourth liquid passage L4 through the second liquid passage L2 as shown by the broken line arrow in FIG. The brake force is supplied to the wheel cylinders 13a to 13d of each brake caliper to generate a braking force on each wheel 15a to 15d. When braking a specific wheel, such as a side slip prevention control device, only the corresponding pressurizing valves 30 and 31 are opened.

  When it is determined in step S1 described above that the automatic brake drive signal is not output, the routine directly ends. On the other hand, when the automatic brake drive signal is detected, the process proceeds to step S2, and the brake characteristics detected by the first and second brake fluid detection means 29a and 29b are read. After that, the process proceeds to step S3, and the change amount of both brake hydraulic pressures for a predetermined time (for example, 0.5 [sec]) is calculated from this brake characteristic.

  When the first and second brake fluid detecting means 29a, 29b are hydraulic pressure sensors, this change amount is obtained from the rate of increase in brake fluid pressure, the rate of increase in acceleration, and the like. In the case of a flow rate sensor, the amount of change is calculated from the integrated flow rate. It should be noted that the first and second brake fluid characteristics and their changes are calculated until the automatic brake drive signal is no longer detected. Further, the processing in step S3 corresponds to the brake fluid change amount calculation means of the present invention.

  Next, the process proceeds to steps S4 and S5, and whether or not the amount of change of the brake fluid detected by the first brake fluid detecting means 29a in step S4 is within a preset specified range, that is, is it within a normal range. Check whether or not. Then, if it is within the specified range, it is determined that the brake fluid pressure passing through the first fluid pressure circuit 22 is normal, and the routine exits as it is.

  Further, in step S5, it is checked whether or not the amount of change of the brake fluid detected by the second brake fluid detecting means 29b is within a preset specified range, that is, whether it is within a normal range. Then, if it is within the specified range, it is determined that the brake hydraulic pressure passing through the second hydraulic circuit 23 is normal, and the routine exits as it is.

  If it is determined in at least one of steps S4 and S5 that the amount of change in the brake fluid pressure is out of the specified value, the process proceeds to step S6, the master piston retracting process is executed, and the routine exits.

  As shown in FIG. 2A, when the driver releases the brake pedal 7, the first and second hydraulic chambers 11a and 11b of the master cylinder 4 communicate with the reservoir tank 5 first, The second master ports 5a and 5b are fully open. Therefore, due to the rotation of the hydraulic pump 26, the brake fluid stored in the reservoir tank 5 passes through the first and second master ports 5a and 5b with a small passage resistance and passes through the first and second hydraulic chambers 11a and 11b. And is supplied to the first and second hydraulic circuits 22 and 23.

  On the other hand, as shown in FIG. 2 (b), the driver is stepping on the brake pedal 7 with an extremely gentle depressing force Fp, that is, the driver is stepping on the brake pedal 7 without intention of the brake operation. In the state, as shown in FIG. 6A, the first and second master pistons 9a and 9b inserted in the master cylinder 4 are pressed, and the opening areas of the first and second master ports 5a and 5b are reduced. It is narrowed down from the fully opened state A1 to the state A2.

  As a result, the first and second master ports 5a and 5b serve as throttles to generate a large passage resistance, which is supplied to the wheel cylinders 13a to 13d via the first and second hydraulic circuits 22 and 23. The flow rate of the brake fluid (flow rate) is limited, and the pressure rise is delayed, resulting in a decrease in brake response. Therefore, in the present embodiment, in step S6, the master piston retracting process is executed to retract the first and second master pistons 9a and 9b, and as shown in FIG. The valves 5a and 5b are closed. In FIG. 6B, the first and second compression springs 12a and 12b are omitted for ease of explanation.

  The master piston retracting process in step S6 is executed according to the master piston retracting process subroutine shown in FIG.

In this subroutine, first, the pressure reducing valves 32 and 33 are opened in step S11, and the process proceeds to step S12, in which the physical amount Mv and the set physical amount Mo as the measured physical amount indicating the supply state of the brake fluid measured from the start of the master piston retracting process. Compare with. Then, the process waits until the physical quantity Mv reaches the set physical quantity Mo, and when it reaches the set physical quantity Mo (Mv ≧ Mo), the process proceeds to step S13, the pressure reducing valves 32 and 33 are closed, and the liquid path at the time of automatic braking is activated. Return and exit the routine.

  When the pressure reducing valves 32 and 33 are opened in step S11, the hydraulic pump 26 is connected to the low pressure accumulator 24 via the third and fourth liquid passages L3 and L4. Therefore, the brake fluid discharged from the hydraulic pump 26 is accumulated in both the wheel cylinders 13a, 13b (13c, 13d) and the low pressure accumulator 24. In particular, since the capacity of the low pressure accumulator 24 is increased, the flow velocity of the brake fluid discharged from the hydraulic pump 26 is accelerated, and the first and second hydraulic pressure chambers 11a and 11b of the master cylinder 4 are relatively accelerated. The flow velocity of the retained brake fluid to the first and second hydraulic circuits 22 and 23 is rapidly increased.

  As a result, the amount of brake fluid sucked out from the first and second hydraulic pressure chambers 11a and 11b per unit time passes from the reservoir tank 5 through the first and second master ports 5a and 5b, and then the first and second The first and second master pistons 9a and 9b are drawn in the braking operation direction due to a sudden increase in the brake fluid flow rate that is greater than the amount of brake fluid that flows into the hydraulic chambers 11a and 11b and is sucked out, as shown in FIG. As shown in, the first and second master ports 5a and 5b are closed.

  The physical quantity Mv read in step S12 is, for example, the elapsed time, the brake fluid flow rate or the brake fluid pressure downstream of the hydraulic pump 26, and the corresponding set physical quantity Mo is the set time, the set flow rate, and the set fluid pressure.

  When the set physical quantity Mo is the set time, this set time is set based on the discharge amount of the hydraulic pump 26 per unit time and the pressure storage capacity of the low pressure accumulator 24, and based on the time during which the low pressure accumulator 24 is in a saturated state. It Further, in the case of the set flow rate, it is set based on the integrated flow rate at which the low pressure accumulator 24 becomes saturated. Further, in the case of the set hydraulic pressure, it is set based on the brake hydraulic pressure when the low pressure accumulator 24 reaches the saturated state. The brake fluid flow rate and the brake fluid pressure of the physical quantity Mv are detected by the first and second brake fluid detection means 29a and 29b.

  Therefore, the brake fluid staying in the first and second hydraulic pressure chambers 11a and 11b of the master cylinder 4 is sucked until the low pressure accumulator 24 reaches a saturated state, and at that time, the master pistons 9a and 9b are pulled in the brake operating direction. Then, the first and second master ports 5a and 5b are closed. Then, since the first and second hydraulic pressure chambers 11a and 11b are communicated only with the first and second supply / discharge ports 14a and 14b, the brake fluid that stays in the first and second hydraulic pressure chambers 11a and 11b. Is sucked toward the first and second hydraulic circuits 22 and 23, and at the same time, the master pistons 9a and 9b are drawn in the brake operating direction.

  As a result, the decrease in flow rate is suppressed, and the brake fluid staying in the first and second hydraulic pressure chambers 11a and 11b is provided to the wheels 15a to 15d via the first and second hydraulic pressure circuits 22 and 23. The brake responsiveness is immediately restored by being supplied to the wheel cylinders 13a to 13d of the brake caliper.

  When the pressure reducing valves 32 and 33 are shut off, the brake fluid accumulated in the low pressure accumulator 24 is discharged toward the hydraulic pump 26 by the urging force of a pressure regulating urging member such as a pressure regulating spring installed therein. It Therefore, the amount of brake fluid discharged from the hydraulic pump 26 increases, and thereby the flow rate ratio (flow rate) of the brake fluid supplied to each wheel cylinder 13a to 13d increases, and the pressure is raised early, The brake can be operated.

  On the other hand, as described above, when the master pistons 9a and 9b are pulled in by the master piston pulling-in process, the brake pedal 7 connected to the master pistons 9a and 9b is rotated in the stepping direction. The extremely gentle depressing force Fp will actuate the braking operation, and the braking response during automatic braking can be further improved.

  As described above, according to the present embodiment, when the automatic brake is operated, the driver slightly depresses the brake pedal with an extremely gentle depressing force not intended for the brake operation, so that the first of the reservoir tank 5 and the master cylinder 4, The opening areas of the master ports 5a and 5b communicating with the second hydraulic chambers 11a and 11b are narrowed to the state A as shown in FIG. 6A, and the brake fluid stored in the reservoir tank 5 is When the flow rate (flow rate) of the brake fluid supplied to the wheel cylinders 13a to 13d is limited by the passage resistance when flowing into the first and second hydraulic chambers 11a and 11b, the brake fluid in the master cylinder 4 is Since the accumulator 24 is made to accumulate pressure via the hydraulic pump 26, the suction is performed by the hydraulic pump 26 from the first and second hydraulic chambers 11a and 11b. The brake fluid amount is rapidly increased that the master piston 9a, 9b are retracted into the brake actuating direction, first, second master port 5a, 5b are closed.

  Then, by closing the pressure reducing valves 32 and 33, the brake fluid staying in the first and second hydraulic chambers 11a and 11b can be supplied to the wheel cylinders 13a to 13d, and the decrease in the flow rate is suppressed. Thus, the brake responsiveness can be immediately restored.

  When the pressure reducing valves 32 and 33 are closed, the brake fluid accumulated in the low pressure accumulator is supplied to the wheel cylinders 13a to 13d via the hydraulic pump 26, so that the brake responsiveness can be recovered more efficiently. it can.

  The present invention is not limited to the above-described embodiment, but the first and second hydraulic circuits 22 and 23 shown in FIG. 1 are merely examples, and the pressure accumulating means is not limited to the low pressure accumulator 24, and the hydraulic pressure The circuits 22 and 23 may be separately provided.

1 ... Brake fluid pressure generation unit,
2 ... Brake fluid pressure circuit,
3 ... Brake control unit,
3a ... Brake fluid monitoring unit,
4 ... Master cylinder,
5 ... Reservoir tank,
5a, 5b ... Master port,
6 ... Brake booster,
7 ... brake pedal,
9a ... the first master piston,
9b ... second master piston,
11a ... the first hydraulic chamber,
11b ... second hydraulic chamber,
13a to 13d ... wheel cylinders,
22 ... First hydraulic circuit,
23 ... Second hydraulic circuit,
24 ... Low-pressure accumulator,
25 ... Gate-in valve,
26 ... hydraulic pump,
27 ... electric motor,
28 ... Bypass valve,
29a ... first brake fluid detecting means,
29b ... second brake fluid detecting means,
30, 31 ... Pressure valve,
32, 33 ... Pressure reducing valve,
Fp ... extremely slow pedaling force,
L1 to L8 ... First to eighth liquid paths,
Mv ... physical quantity,
Mo ... Set physical quantity

Claims (6)

A brake operation unit operated by the driver,
A master cylinder that is connected to the brake operating unit and that generates a brake fluid pressure with an operation amount of a master piston according to an operation amount in the brake operating unit;
A reservoir tank for supplying brake fluid to the master cylinder via a master port,
A wheel cylinder that generates a braking force on a wheel with brake fluid pressure from the master cylinder,
A hydraulic circuit connecting the master cylinder and the wheel cylinder,
Pressure accumulating means provided in the hydraulic circuit for accumulating the brake fluid supplied to the hydraulic circuit;
A brake fluid change amount calculating means for obtaining a change amount of the brake fluid passing through the hydraulic circuit,
When the automatic brake operating condition is satisfied, the hydraulic pump interposed in the hydraulic circuit is driven to supply the brake fluid on the master cylinder side to the wheel cylinder independently of the operation of the brake operating unit. In a vehicle automatic brake device including a brake control means for
The brake control means further includes a brake fluid monitoring means for monitoring a change amount of the brake fluid supplied to the wheel cylinder when the automatic brake operating condition is satisfied,
The brake fluid monitoring means, when the amount of change obtained by the brake fluid change amount calculating means is out of a preset specified value, the brake fluid on the master cylinder side is stored in the pressure accumulating means via the hydraulic pump. After accumulating pressure, the measured physical quantity that detects the supply state of the brake fluid to the hydraulic circuit is compared with the set physical quantity, and when the measured physical quantity reaches the set physical quantity, the accumulation of the brake fluid to the pressure accumulating means is shut off. An automatic brake device for a vehicle, characterized by performing a brake fluid drawing process. The master cylinder is a tandem type, the master cylinder and the wheel cylinder are connected via the hydraulic circuit of two systems,
If the change amount of the brake fluid passing through at least one of the two hydraulic circuits is out of a preset specified value, the brake fluid monitoring means draws the brake fluid into both hydraulic circuits. processing automatic brake device for a vehicle according to claim 1 Symbol placement and performing. The set physical quantity is the set time, and the measuring physical quantity, any one of claims 1-2, wherein said brake fluid monitoring means is elapsed time since starting the brake fluid retraction process 1 An automatic brake device for a vehicle according to the item. The set physical quantity is set flow rate, and the measurement physical quantity is the hydraulic pump downstream of the vehicular automatic brake system as claimed in any one of claims 1-2, characterized in that the flow rate of the brake fluid. The set physical quantity is set the brake fluid pressure, and wherein the measurement physical quantity is a vehicle automatic brake system as claimed in any one of claims 1-2, characterized in that the brake hydraulic pressure of the hydraulic pump downstream . The set physical quantity vehicular automatic brake device according to any one of claim 1 to 5, characterized in that is set based on the pressure accumulation capacity of the accumulator means.

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